1. Field of the Invention
The present invention relates to a control device for a vehicle including an engine stop and start device which automatically carries out a stop and a restart of an internal combustion engine of the vehicle mounted with the internal combustion engine and a regenerative charging device which charges a battery using energy during deceleration of the vehicle.
2. Description of Related Art
As a fuel efficiency improving technique for a vehicle mounted with an internal combustion engine, an idling stop system is known.
The idling stop system is also called engine stop and start device. The idling stop system automatically performs each of a temporary stop of the engine and a restart of the stopped engine.
In a control device for a vehicle including the engine stop and start device in the past, when the engine is restarted, for example, a starter motor is started to restart the engine.
In the restart, electric power of a battery for starting the starter motor is necessary.
If the electric power of the battery is not accumulated enough for starting the starter motor, the engine may not be able to be restarted. Therefore, it is necessary to always monitor an accumulation state of the electric power of the battery.
As a related art concerning the control device for a vehicle, there is a technique disclosed in Japanese Patent Application Laid-Open Publication No. 2003-35176. In Japanese Patent Application Laid-Open Publication No. 2003-31576, a balance of charging and discharging is calculated by cumulatively integrating charging and discharging capacities of a storage battery from an engine start or restart to the next engine restart during the idle stop-and-go driving and the balance is compared with a threshold set in advance. This makes it possible to determine a charging state without quantitatively calculating a set value of a battery capacity of the storage battery and surely perform an engine restart after an idling stop.
It is known that fuel injection is stopped when a vehicle is decelerated using an engine brake and the fuel injection stop can contribute to fuel saving. There is a method of driving, simultaneously with the deceleration of the vehicle, an alternator (a generator) using energy during the deceleration of the vehicle and regenerating the energy as electric power to charge a battery.
The engine stop and restart by the engine stop and start device may be enabled by the electric power obtained by the regeneration. Therefore, it is desirable that the engine can be stopped as much as possible taking into account a charging amount of the battery by the regeneration.